Care Home A is a large private hospital in Widnes. As such it is bound to comply with the approved code of practice.

Problems arose when, during the routine Legionella Species undertaken as partmof the water safety groups compliance practice. High levels of legionella ( 10000cfu) were found in the system.

The hot water temperature was increased from 60°C to 72°C. Adding to this a high level disinfection was carried out on site and the outlets resampled. The results came back and the levels of Legionella was higher than the initial sampling by 2000cfu.

• Patients groups varied from minor or low Legionella risk to high risk patients
• Site engeering levels already streached
• Fairly large Care Home with a mixture of and old and new pipework, inacessable
deadlegs and deadends streached over separate sites six sites
• Solution had to be safe, robust and easily monitored
• Cost effective as budgets were strained

Create a long term strategy and engineering solution that is not only robust, cost effective and compliant

4i Water Services considered various water treatment methodologies. 

• UV is an excellent method of disinfection but requires pre-filtration and has no residual. Since the problems were coming from colonisation post-mains within the system, in order to be effective, UV would have to be installed on all the outlets. This was cost-prohibitive.
• Ozonolysis, an excellent method of disinfection, ozonolysis is a very effective disinfecting agent in very dirty situations with a residual for direct real time measurement. However, it is also quite expensive to run the electrical generation plant and the aggressive oxidising nature of ozone was expected to drastically shorten the life of the system. 
• End of Line (EOL) or Point of Use (POU) Filtration. This can reduce bacteria results in water sent to patients to zero but does not address the problem. The bacteria remain in the system, so it is a technology to reduce exposure rather than fundamentally reduce the possible harm 
• Chlorine dioxide. When produced in sufficiently high purity chlorine dioxide is an online potable biocide, meaning that it can be dosed directly into drinking water. Stringent limits on total oxidants are set by the Drinking Water Inspectorate, so any potential chlorine dioxide unit must be able to ensure that the total chlorine dioxide, chlorites and chlorates produced as by-products of its generation remain below 0.5 mg/L. Chlorine Dioxide is a more effective biocide than chlorine, requires less contact time to achieve disinfection. 

The final approaches were deemed as the most appropriate. Installing a Februus MEDI-SentineI water purification system, a chlorine dioxide unit specifically designed to cope with the high flow rates and water usage of the clinical setting. 

• The Februus MEDI-Sentinel has engineered out issues that have caused low yields and poor dosing in the past.
• Remotely monitored and operated, this means that onsite and offsite personnel can be alerted to problems or check the operation of the unit through a smartphone app.
• Highly accurate water meter 99.998%, this means that rather than dosing 50mg/100L like a K100 mechanical water meter, it doses 0.5 mg/L avoiding the issues of "slugs" of treated and untreated water. 
• High purity dosing of chlorine dioxide, this means that the chemical is used efficiently and the customer is not paying for waste. 
• Safe, robust and easily maintainable system with proven C102 delivery. 
• BMS Link-up option to manage other plant through our PLC Operating System. This can be used as another safety measure, or as a control, putting control into the site managers hands.
• DWI-Approved method of continuous disinfection of drinking water which ensures statutory compliance.
• BS 8558:2011 Approved method of continuous disinfection which ensures compliance with the approved code of conduct 
• Water authority approved installations which ensure compliance with the Water Supply Regulations (1999). 

Monitoring the solution
Frequency Task
Daily CDU dosing equipment and physical check on chemical levels - confirm against PLC readings 
Weekly Remote monitoring report to be sent to Estates Manager showing water usage, stock and dosing levels - checked against onsite engineers reports 
Weekly CL02 testing tank and sentinel points on both hot and cold services 
Monthly Random Legionella and Psudomonas Sampling 
Monthly 12% of outlet sampled for CL02 levels 
Quarterly Review results with 4iWS and Estates Team 

12 months later...

After running the system the for 12 months, the increase in both Legionella and Pseudomonas sampling as well as the Chlorine Dioxide the results have been as follows: 

Chlorine Dioxide
These samples were carried out by both 4i Water Services and the site maintenance staff. 

The vast majority of samples fell into the 0.1-0.5 ppm range. This means that no overdosing took place and underdosing took place on only three per cent of samples in 12 month achieving a correct dosing rate 100% of the time.
Random legionella samples were taken according to the latest standards in microbiological sampling and sent to a UKAS laboratory for culturing and analysis over a 12 month period. Not one sample showed the detection of legionella spp. The first round of clear results came three days after the dosing unit was installed. All subsequent sampling results came back clear. 

The site had an annual spend of
• Remedial works carried out by incumbent water treatment provider - £42,000 
• Further remedial works recommended - £22,400

Total cost of £64,400 

4i Water Services supplied 

• One Februus Medi Sentinal Chlorine Dioxide dosing systems
• One purpose built chemical dosing storage shed to supply all six sites
• Training and test kit to measure the performance of the system
• 24/7 remote monitoring of water usuage, chemical usage and dosing levels
• Chemical, servicing and maintenance on both systems
• Initial cost of £24,000 per annum
• Ongoing maintenance and chemical costs in the region of £3000 per annum 

Due to efficacy of Februus Medi Sentinal dosing system, there has been no need to carry out any high level disinfections since. The site staff and patients are now benefiting from from clean and safe water system. 


When faced with old buildings with various pipework configurations, inaccessible deadlegs and deadends this was always going to be a difficult problem to solve. This was made even more difficult due to the nature of high risk patients within the hospital. 

The Februus Medi Sentinal Dosing System has proven to be realiable, robust, cost effective chlorine disoxide disinfection system. 

The results broken down: 

• Chlorine dioxide samples were taken over a 12 month period. Less than 3% fell under the recommended 0.1ppm while zero fell over 0.5ppm. 
• Legionella samples taken - zero positives. 
• Psudomonas samples taken - <1% positive on the pre samples (all under 
10cfu) and zero on the post samples. 

Following on from the success of this unit's performance the Group have installed 12 further units across its portfolio of high risk sites. All the high risk sites have shown similar results in reductions of both positive samples and emergency disinfections. 

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